1Biomedical Engineering, University of Alberta,
Edmonton, Alberta, Canada; 2Cardiovascular Physiology and
Rehabilitation Laboratory, University of British Columbia, Vancouver, British
Columbia, Canada; 3Physical Therapy, University of Alberta,
Edmonton, Alberta, Canada; 4Division of Cardiology, University of
Alberta, Edmonton, Alberta, Canada

Non-rigid registration of serially acquired MRI lung
images provides a direct method for quantifying lung ventilation with minimal
user interaction. In-plane deformations are translated into local volume changes,
which are combined with respiration rates to measure regional ventilation, and
summed over the lungs to determine total lung ventilation. Simultaneous
measurement of total ventilation over a large range of ventilation rates (3-35
liters/min) using gold standard spirometry correlated well with MRI rates (R2=0.88).
Regional ventilation maps show significant differences (p<0.05) between
ventilation in anterior (1915% volume increase) vs. posterior (3016%) lung
regions, and a continuous chest-to-back gradient in all subjects.